/*
 * Copyright (c) 2018, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.svm.core.c;

import java.io.PrintWriter;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Collections;
import java.util.List;

/**
 * Defines the C header file for entry points enclosed by the annotated class or method.
 *
 * The {@code CHeader} annotation can be placed on methods and types: When placed on a method, this
 * method will be included into the defined header file. When placed on a class, all entry points in
 * that class (as well as the enclosing classes) will be included to the defined header file.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
public @interface CHeader {

    /**
     * Class that defines the header file properties.
     */
    Class<? extends CHeader.Header> value();

    interface Header {
        /**
         * Name of the header file.
         */
        String name();

        /**
         * List that contains the {@code Class<? extends CHeader.Header>} instances that declare
         * dependencies of this header file.
         */
        default List<Class<? extends Header>> dependsOn() {
            return Collections.emptyList();
        }

        /**
         * Writes a preamble after the dependencies and before the list of included methods.
         */
        @SuppressWarnings("unused")
        default void writePreamble(PrintWriter writer) {
        }
    }

}
